A mechanical automotive vacuum pump is mechanically driven by an engine of the automotive vehicle. The automotive engine is, in most cases, an internal combustion engine.
EP 0 264 749 A2 describes an automotive vacuum pump with a pump rotor with a chamber section and a bearing section. The rotor body is provided with a cylindrical bearing surface which together with a corresponding bearing surface of the pump housing defines a friction bearing at one axial end of the pump rotor. The pump lubrication is realized by a lubricant which is first injected into the rotor interior. The lubricant is pressed from the rotor interior via gaps between the pump rotor and the vane or the pump housing into the pumping chamber. The lubricant is pumped together with pressurized air from the pumping chamber through an air outlet into an outlet chamber. From the outlet chamber, the lubricant is pumped into a circular ring groove which is provided at the cylindrical bearing surface of the pump housing. The lubricant pressure at the friction bearing directly depends, for example, on the pneumatic outlet pressure of the pump.